Dishwashing machine

ABSTRACT

A dishwasher ( 1 ) is proposed, in which the program sequence can be controlled as required. According to the invention, this is achieved by providing a radar sensor ( 12 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dishwashing machine, and moreparticularly, to a dishwashing machine in which the program sequence ofdishwashing can be controlled more flexibly.

2. Discussion of the Related Art

Dishwashing machine normally use fixed program steps, which arecontrolled by electromechanical switching mechanisms, or by electroniccontrollers. The individual program steps are in this case alwayscarried out in a predetermined manner, irrespective of the operatingstate of the machine, for example the load, the amount of dirt on thedishes or in the washing water, etc. If the spray arm is block, forexample by the dishes arm is blocked, for example by the dishes beinginserted incorrectly, if the nozzle are excessively dirty, etc, thisresults in a poor dishwashing result.

A dishwashing machine in which an optical sensor was provided fordetection of the spray arm movement is known from the document DE 40 18048 A1. This sensor unit operates in the manner of a light barrier, inwhich case it is possible to detect the passage of a reflective surfaceon the spray arm in corresponding time intervals, by means of the sensorunit.

SUMMARY OF THE INVENTION

The present invention includes a dishwashing machine having a sensorunit, by means of which it is possible to detect dynamic processesbetter.

A dishwashing machine according to the invention is accordinglydistinguished by the provision of a Doppler radar sensor. The Dopplerradar sensor allows a large number of different functions to bemonitored. Overall, the capability to detect various types of operatingand control parameters by means of a radar sensor allows betterregulation and control and the dishwashing machine operations.

The frequency difference between the emitted and reflected wave isevaluated by means of the Doppler radar sensor. This difference, whichis also referred to as the Doppler frequency, represents a measure ofthe relative rate of movement between the sensor and the respectivereflection surface. The Doppler radar is thus particularly highlysuitable for monitoring dynamic processes.

In one particular embodiment of the invention, the radar sensor isdirected into the interior of the washing chamber. A radar sensordirected in such a way is able to provide information about theprocesses taking place inside the washing chamber. This information mayrelate, for example, to the washing liquid, the dishes that have beeninserted, or else to the dishwasher components.

The washing chamber wall is advantageously at least partially formedfrom plastic, so that the radar sensor can be arranged behind thisplastic, outside the washing chamber, and both the antenna and theelectronic circuit, including the electrical connections, are protectedfrom damaging influences resulting from the washing process. The radartechnology itself is distinguished in that it can operate despite dirtor cloudiness in the interior of the washing chamber.

In the case of a dishwashing machine having a plastic housing, the radarsensor can be arranged at virtually any desired point on the outside ofthis plastic wall. In the case of stainless steel housings, as isgenerally the case, at least in Europe, the radar sensor can be fittedto a plastic insert, which is inserted into a recess in the washingchamber housing.

In one particular embodiment, the radar sensor is fitted to an insertpart, which is already used in any case in conventional dishwashers atthe moment. This may be, for example, the plastic insert which isalready arranged on the sump of the dishwasher and contains filterinserts. Another option is also to integrate the radar sensor in ametering apparatus for detergent.

In principle, the radar sensor can be fitted anywhere where there is awindow into the interior of the stainless steel housing, so that theradar beams are not screened.

The radar sensor is advantageously arranged in the door of thedishwasher. In this case, the radar sensor is fitted in the physicalvicinity of the electronic controller, which normally arranged in thedoor area, so that the connecting lines can be fitted without anyproblems.

An arrangement such as this is present in the door area, especially inconjunction with the metering apparatus, since this arrangement isalready accommodated in the door area, for simple filling and foroperation via the machine controller.

The radar sensor allows program control of the dishwasher as a functionof the widely different parameters which can be detected by means of theradar sensor. An appropriately designed evaluation and control unit isadvantageously provided for this purpose. The evaluation itself can becarried out, for example, by comparing the measurement spectrum with areference spectrum recorded in predetermined operating conditions.

This allows a large number of monitoring processes to be carried outusing one and the same sensor. If necessary, a number of sensors canalso be used, for different monitoring tasks. It is also feasible to usea sensor with different emission frequencies, in order to achieve moreversatile use. In addition to a radar sensor arranged in a fixedposition, it would invariably also be possible to use a moving sensor,although a rigidly fitted sensor is to be preferred, owing to thecorresponding reduction in the manufacturing complexity.

The radar sensor can be used, for example, for spray arm monitoring, inorder to detect whether a spray arm is rotating correctly inside thedishwasher or whether its rotation is being interfered with, or in theworst case is even being blocked. In this case, if the defect cannotitself be rectified, an alarm signal is produced for the machineoperator.

A radar sensor can also be used to detect the load state of thedishwasher. This is done either by using standing waves or else by usingthe relative movement between the dish basket and the sensor, making useof the Doppler effect for load monitoring. The monitoring process could,for example, be carried out during the process of closing the door, ifthe sensor is arranged in the dishwasher door.

It would also be possible to use the radar sensor according to theinvention to monitor the filling level. This can be done either bydirectly using the reflection from the liquid surface or else by usingsecondary effects, for example the influence on the vibration responseof the washing chamber housing caused by the filling level.

A radar sensor according to the invention can also be used for foammonitoring or for spray pattern monitoring during the washing process.The surface of water droplets are used as reflection or refractionsurfaces, so that the radiation pattern which is detected by the sensoris considerably influenced by this.

Furthermore, various data can be detected by means of the radar sensor,which is noticeable by virtue of secondary effects, for example theinfluence on the vibration response of the machine.

As for example, it would be feasible to monitor bearings, for example ofthe water pump or the state of filters, by measuring such secondaryeffects.

Temperature measurement would also be feasible. A temperaturemeasurement could be carried out, in particular, by means of suchsecondary effects, for example by detecting the vibration response of atest body or by detecting temperature-dependent length expansions.

Furthermore, the radar sensor could be used to monitor the amount ofdirt, the circulation or some other state of the washing liquid. Thestate of the washing liquid influences the reflections of the infectedradiation, as does the configuration of the surface, so that this canalso be used to carry out monitoring by means of the radar sensor.

In principle, all dishwasher units can be monitored for correctoperation by means of a radar sensor, in which case it is eitherpossible to detect the state of individual components directly, or elseto detect secondary effects, as stated above.

In addition to said function, a radar sensor can also advantageously beused to detect the moisture content or vapor level. This isadvantageous, for example, in order to detect a drying profile and,possibly, for controlling the dishwasher. The moisture content insidethe washing chamber can have a direct influence on the sensor signal, orcan be detected indirectly via further parameters, for example thedroplet size, the state of a test body or the like. The droplet size andshape or state data of a test body wetted with the washing liquid canalso, for example, be used in order to make statements on the state ofthe washing liquid, for example its detergent content.

A test body which reacts to the respective measurement variable andwhose state changes can be detected by the radar sensor can in generalalso be used for detecting other measurement variables.

Furthermore, a radar sensor according to the invention also makes itpossible to monitor the state of the ion exchanger, which must beregenerated at the latest when its ion exchanger capacity is exhausted.

The brine which is normally used for regeneration of an ion exchanger inthe dishwashing machine can also be monitored using a radar sensor. Thebrine state can in this case be measured directly by the influence ofthe charge carriers contained in it on the sensor signal, or else bymeans of the state of a float in the interior of the brine container.

One further advantageous use of a radar sensor is detection of thedetergent level in an appropriate metering appliance. This can be used,for example, to produce an alarm signal if the detergent needsreplenishment. This application is also particularly advantageous in thecase of dishwashers which can hold a supply of detergent for a number ofdishwashing cycles. This is already prior art for the metering of liquidrinsing agents. However, in principle, corresponding multiple washingcycles are also feasible for the addition of cleaners.

Finally, a radar sensor can also be used for flow measurement inside aline. Flow measurement is already carried out in present-day dishwashersby widely different means, and is used for widely differing purposes. Byway of example, flow measurement has been required for a long time inconnection with the hardness level of the tap water being supplied, inorder to determine the state of the ion exchanger.

The use of waveguides, which open at the appropriate outlet point, wouldalso be feasible in order to use the radar sensor objectively atdifferent locations. The radiation lobe of sensor can likewise be shapedby appropriate configuration of the antenna with or without a waveguide,such that one or more areas in the interior of the dishwasher areilluminated objectively.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment is illustrated in the drawing, and will beexplained in more detail in the following text with reference to thefigures.

In detail:

FIG. 1 shows a schematic cross section through a dishwasher and

FIG. 2 shows a plan view of the inside of the door of a dishwasher.

FIG. 1 shows a schematic cross section of the dishwasher 1 with awashing chamber 2. Dish baskets 3, 4 are located in the washing chamber2 under each of which a spray arm 5, 6 is arranged, such that it canrotate.

DETAILED DESCRIPTION OF THE PRFERRED EMBODIMENT

A dishwasher door 7 is fitted to the front face such that it can rotate,as is indicated by a rotation shaft 8. A metering apparatus 9 for addingdetergent is located in the dishwasher door 7.

A sump container 11 is located in the base 10 of the dishwasher 1 andcontains, for example, the normal filters and water outlet.

In the present exemplary embodiment, a radar sensor 12 is providedunderneath the sump container 11 and illuminate the entire interior ofthe washing chamber 2, in this arrangement.

FIG. 2 shows a further option for the arrangement of a radar sensor 13.In this case, the radar sensor 13 is located in the metering apparatus 9which, in the normal way, comprises a flap 14 for closing a detergentchamber, an outlet opening 15 for metering the rinsing agent, and aviewing glass 16 and a replenishment opening 17 for the rinsing agent.The metering apparatus 9, which has already been described withreference to FIG. 1, is inserted into the dishwasher door 7. Theevaluation and control unit can also be arranged in the interior of thisdoor, as is indicated in FIG. 1. At the location of the evaluation andcontrol unit 18 indicated in FIG. 1, this can be connected directly tothe keys and other operating members required to operate the machine.

The dishwasher according to the invention can be controlled as afunction of the respective operating conditions. Thus, for example, theamount of water and the amount of detergent can be metered depending onthe load level. The pump pressure can be varied as a function of thespray pattern recorded in the interior of the dishwasher. If required,even controllable nozzles are feasible. The spray pattern could bevaried as a function of the type of dishes located in the interiorsince, normally, pots and pans produce a different sensor signal from,for example, glasses or porcelain. The duration of the individualprocess steps can also be varied as a function of such parameters. Thus,for example, the dirt content of the washing water can also be used tocontrol the machine in order, if required, also to introduce a furtherwashing step into the washing program.

In principle, the sensor signal is available for evaluation of allpossible desired information provided only that, according to theinvention, a radar sensor is fitted to the dishwasher or to an insertpart in the dishwasher.

LIST OF REFERENCE SYMBOLS

1 Dishwasher

2 Washing chamber

3 Dish basket

4 Dish basket

5 Spray arm

6 Spray arm

7 Dishwasher door

8 Rotation shaft

9 Metering apparatus

10 Base

11 Sump container

12 Radar sensor

13 Radar sensor

14 Flap

15 Outlet opening

16 Viewing glass

17 Replenishment opening

18 Evaluation and control unit

What is claimed is:
 1. A dishwashing machine, comprising: anelectromagnetic sensor unit, which includes a transmitter and areceiver; and a washing chamber, wherein the electromagnetic sensor unitcomprises at least one Doppler radar sensor directed at the washingchamber.
 2. The dishwashing machine according to claim 1, wherein the atleast one radar sensor emits radar signals and includes a waveguide forspecific emission of the radar signals.
 3. The dishwashing machineaccording to claim 2, further comprising an evaluation and control unitfor evaluation of the signals from the at least one radar sensor and forcontrol of a program sequence of the dishwashing machine, taking intoaccount of the information obtained from the evaluation.
 4. Thedishwashing machine according to claim 3, wherein at least one washingchamber wall includes a recess and the at least one radar sensor isarranged on an insert part which can be inserted into the recess.
 5. Thedishwashing machine according to claim 1, wherein the washing chambercomprises walls, at least one of the wall being composed at the leastpartially of plastic, and the at least on radar sensor is arrangedbehind the plastic, outside the washing chamber.
 6. The dishwashingmachine according to claim 1, further comprising a sump containerlocated at a base of the dishwashing machine and the at least one radarsensor being arranged on a plastic part surrounding the sump container.7. The dishwashing machine according to claim 1, further comprising ametering apparatus for adding detergent and rinsing agent, the at leastone radar sensor being fitted to the metering apparatus.
 8. Thedishwashing machine according to claim 7, wherein the at least one radarsensor detects a detergent level in the metering appliance.
 9. Thedishwashing machine according to claim 1, further comprising a door andthe at least one radar sensor being arranged in the door.
 10. Thedishwashing machine according to claim 1, further comprising at leastone spray arm and at least one dish basket for loading dishes located inthe washing chamber under each of the at least one spray arm and whereinthe at least one radar sensor monitors the operation of the at least onspray arm.
 11. The dishwashing machine according to claim 10, whereinthe at least one radar sensor monitors the dishes located in the atleast one dish basket.
 12. The dishwashing machine according to claim 1,wherein the at least one radar sensor monitors a filling level in thewashing chamber.
 13. The dishwashing machine according to claim 1,wherein the at least one radar sensor monitors foam and spray pattern inthe washing chamber.
 14. The dishwashing machine according to claim 1,wherein the at least one radar sensor detects a defection of componentsof the dishwashing machine.
 15. The dishwashing machine according toclaim 1, wherein the at least one radar sensor detects a temperatureinside the dishwashing machine.
 16. The dishwashing machine according toclaim 1, wherein the at least one radar sensor detects vibration of thewashing chamber.
 17. The dishwashing machine according to claim 1,wherein the least one radar sensor detects the moisture content in thewashing chamber.
 18. The dishwashing machine according to claim 1,further comprising a brine for regenerating an ion exchanger and the atleast one radar sensor monitoring the operation of the brine.
 19. Thedishwashing machine according to claim 1, wherein the at least one radarsensor detects cloudness of washing liquid in the washing chamber. 20.The dishwashing machine according to claim 19, wherein the at least oneradar sensor detects a detergent content in the washing liquid.
 21. Thedishwashing machine according to claim 1, wherein the at least one radarsensor measures a fluid flow in the washing chamber.
 22. An insertelement for inserting into a recess in at least one wall of a washingchamber of a dishwashing machine, comprising at least one radar sensor,the at least one radar sensor emitting radar signals and the insertelement being made at least partially of a material which does not blockthe radar signals.